Nikon users say that recent firmware update has stopped third-party batteries from working

The update was supposed to report remaining charge level more accurately for Nikon's EN-EL14a lithium-ion battery, however some users have found that it has caused incompatibility with third-party batteries

Users of the Nikon D3100, D3200, D5100, D5200 and Coolpix P7700 have been affected by November’s firmware update, which has unexpectedly rendered third party batteries incompatible, as well as making it impossible to use Nikon batteries in third-party battery grips.

The update was claimed to simply improve accurate detection of remaining life for Nikon’s EN-EL14a battery, as well as generally improving battery performance.